There is a Dutch expression which, literally translated, says 'old age comes with deficiencies' and that is not beside the truth. The older we get, the more likely we encounter physical inconveniences and are more susceptible to all kinds of diseases and medical conditions. Health care, medical equipment and medications can run up the bill rather quick, especially when you don't have sufficient or proper coverage.
Being eligible for Medicare does not automatically mean all your medical expenses are covered. You probably need a Medicare supplement to close the gaps in your insurance where it concerns deductibles and co-pays and it would be a good idea to shop around, compare and find the cheapest Medicare Supplement available.
This doesn't have to be a painstaking and long, drawn out process; you can already find what you need by visiting just one site on the Internet. Even when you think you already got it covered, it could turn out to be well worth it!